On Walmart sponsoring homosexual events...
Part of the homosexual agenda is to win the biggest companies in the world, since the rest follow the biggest, when it comes to endorsement and benefits policies. So they are targeting Walmart and winning. The result will be that in a decade or so almost all companies will be treating homosexually active couples as legitimately married people. If they can't win politically/legally, they will try industrial policy. Walmart's decision is an amorally, economic one, I'm sure, neither flagrant nor stupid. Their idol is not homosexuality but money.
Somebody mentioned the mark of the beast in Revelation. This is more relevant than you may realize. The original context of this was the shopping mall and stock exchange of Ephesus. To get into the market, you had to sprinkle incense to (i.e., worship) Caesar. Then you were given a ticket (mark) to show you had a right to be in the market. The point: society's expectations of everyone's priorities kept the early Christians excluded from society - they had to find a way to meet most of their needs from each other. They literally had to drop out of society sometimes, in order to keep from idolatry.
Walmart only asks for *money* to get into their stores so far :) (Everyone take out your Sam's card and repeat: "This is NOT the mark of the beast.") There are no altars there. Regardless of how they use their money, it is not immoral to buy something at Walmart at this point. If there WERE an altar to worship at to get in, your presence inside would be immoral without spending anything. Use of money is not the issue. The dollars in your wallet/purse right now were maybe handled by someone buying drugs, sex, or something less-sensationally immoral. Sin is not physically contagious, though it should repulse us on a gut level.
At the same time, we would do well to support places we know are moral, or at least places where we aren't aware of supporting immorality.
And we should be preparing ourselves to sacrifice economically, in order to stay faithful to the true God. The time may come when the culture demands our personal lip-service type of worship to their gods (like sprinkling incense on an altar). It would likely look like signing a contract these days, and refer to the "good of the people." Then we need to be willing to give up the market on which we are so dependent.
As far as food sacrificed to idols: there are two ways for someone to inform you of this. One is a weaker brother, who says, This steak was consecrated to Athena; how can you buy and eat it? This context seems to be in 1 Corinthians 8. To which Paul says, don't eat it, so as not to sear the weaker brothers' conscience. The second way is for an unbeliever to flagrantly brag to you: "THIS is ATHENA'S steak." This context seems to be in 1 Cor 10:27-28, to which again Paul says, don't eat it, so as not to give the impression that you endorse Athena. This latter pushes me toward not shopping at Walmart.
But notice that the difference is our knowledge (1 Cor 8:6-7; 10:27-28) and the glory we give (1 Cor 10:31). Believe it or not, Paul is endorsing a "don't ask, don't tell" policy here. He wants Christians to be as actively engaged in the marketplace as possible, without compromising their integrity. One way to accomplish this is by not bringing up whether a temple devoted this particular steak to an idol's glory. If you don't know, then YOU can give glory for it to the true God. If someone beats you to the punch and says, "This steak was cooked for Dagon's glory," then you need to sit it out. But notice that Paul would rather have us be proactive in the public square, glorifying God, than reactive - boycotting places for their idolatry. He doesn't want us giving ground to idols, when they claim part of creation as "theirs." Technically we are not morally constrained by others from partaking of anything in creation which God made for us to enjoy, within His law. Satan can't come in and say "Walmart's mine," and keep us out. Neither can the homosexuals.
The issue is who we give glory to, intentionally or otherwise. And the homosexual lobby is CERTAINLY pushing for society to give glory to homosexual desire and behavior these days. The answer isn't to retreat wherever they are active, but to love them, persuade them of the harm they do to themselves, and point them to a loving Father who made them for something better.
1. When you go out to eat at a restaurant, be sure to give thanks to God together out loud. Give God the glory before others. Not in a loud, "look at us" way. But also not in a cowering, "quiet so no one can hear" way.
2. If your conscience says to not go to Walmart, don't go. Paul would describe you as a weaker brother, but this doesn't make you an inferior Christian. For balance with your "stronger" brothers, read 1 Cor 8:4-6; Romans 14:14, 20, 22, remember it is God's Word, and remember that we are not called to be more "righteous" (using our own standards) than God commands. But if you aren't convinced in your conscience that Walmart is a moral option, then it is a sin for you to go, even if you know in your head it's alright. As you go elsewhere and see other Christians with Walmart bags in their homes, submit to your elders' judgment if they don't censure members for going to Walmart. There are times to engage the culture, even if it appears to others you are compromising. Just don't use "engage the culture" as a cloak to save a few bucks if there are better places to shop. (Engaging the culture by shopping at Walmart would be supporting God-glorifying products and avoiding sinful ones they sell - voting with your dollars).
3. DON'T go researching what every company you patronize is supporting. Let God deal with their idolatry. He has given you the ability to receive the fruit of their idolatry and transform it into a means of glorifying Him.